finally i've added coupon codes

coupon codes can have two types of values: access to an exclusive
ticket type limited to a number of items; access to exclusive seats
coupon codes can be reedemed on dates step
rails notifies node about the session having access to exclusive seats
many improvements and fixes

orders will automatically marked as paid if the total is zero, the
payment step will be skipped if so
address fields get prepopulated if user is logged in as member
added exclusives seats to key
fixed some optical flaws
many other improvements
ordering process now looks prettier

fixed some things to make it valid html5
many improvements
bugfixes
added coupon management page
coupons can now be sent